The Web is shaping the way we communicate and live. It would therefore be beneficial to have a truly trustworthy Web. However, a systematic model of our relationship with the Web is missing, and this makes such a trustworthy Web an elusive target. The Foundations of a Trustworthy Web presents a thorough description of a model that enables the systematic analysis of the impact that the Web has on society, thus facilitating a discussion about the construction of a trustworthy Web. It is a self-contained introduction to another book, The Trustworthy and Trusted Web by the same author. The model presented in this monograph incorporates the Web into the theory of social systems, and analyses how the existence of the Web alters the way in which society creates its reality. Against this background, it defines the position and role of trust and trustworthiness, as well as the social function of the Web, all in the dual perspective of social sciences and technology. This is an excellent book f r anyone who is interested in learning about modelling the relationship between society and information technology, specifically the Web. It is comprehensive and informative in analysing the current situation while also delivering a visionary yet pragmatic exploration of the social purpose of the Web.